Electron-tube system



Nov. 2 1926. 1,605,735

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BY ATTORNEY `Patented Nov. 2, 1926.

UNITED STATES y News PATENT oFFlCE;

CLINTON W. HOUGH, OI BOONVILLE, NEW YORK, ASSIGNOB TO WIRE!) RADIO, INC.,

OF NEW- YORK, N. Y., A CORPORATION OF- DELAWARE. i

ELECTRON-TUBE SYSTEM.

Application led Ianuary 16, 1926. Serial No. 81,826.`

My invention relates broadly to power supply circuits for electron tubes, and more particularly to a method of operating electron tubes from a source of alternating cur-` rent supply without transformation.

One of the objects of my invention is to provide a-method of operating electron tubes from an alternating current supply without the necessity of inter-positioning a transformer between the electron tube circuits and the power supply system for supplying both cathode heating current and plate potential for the operation of the electron tube.

Another object of my invention is to provide a construction of electron tube which ma be operated froma source of house lig ting current without the necessity of employing battery supply systems with all of the inherent disadvantages thereof.

Another object of my invention is to provide a construction of electron tube which may be operated from a source of alternating current supply in which the cathodels divided into two portions with a resistance interposed therebetween and sets of grid and plate electrodes provided adjacent the electron emitting portions in such manner that the plateJ electrodes function when connected with external circuits in cooperation with the cathodes as double wave rectiflers of the A. C. supply which is impressed across the filamentfor supplying the direct current plate potential for the tube system. 4

Still another object of my invention is to provide an arrangement of cathode for an electron tube by which a drop substantially equal tothe impressed volta e may be obtained across the cathode and ternating current supplied thereto and rectified for supplying the potential for the plate c1rcu1t of the electron tube.

Other and further objects of my invention will be understood from the specification hereinafter following by reference to the accompanying drawings, in which:

F1 re 1 illustrates diagrammatically the princ1ples of my invention; Fig. 2 shows a plurality of electron tubes constructed 1n accordance with my invention and connected in a cascade for the amplification of signaling energy; Fig. 3 is an enlarged fragmentary view of one form of cathode construction which may be employed in the electron tube construction of my inventiong( and v connected between the cathodes.

,In a radio receiving apparatus in which a multiple number of tubes is employed for` amplifying relatively feeble incoming .sig-l naling energy, it has been proposed to employ alternating current as a source of power supply in the operation of the tube clrcuit, but such installations have been relatively complicated and in attempting to Iem-l ploy the usual construction of electron tube for such operation it has not been entirely satisfactory by reason of hum and undesired noises produced in the sensitive amplification system by virtue of the existence of disturbing currents in the am liication system aria mg from the source o low frequency power,` supply. In such apparatus it 1s also necessary to provide transformer equipment and independent rectifier tubes for securing the plate potential.' By my invention I provide a construction of electron tube which may be operated from the usual source of residence lighting current w'ithout the interposition of a transformer between the tube system and the power supply system and without the necessity of employingy an in dependent rectifying tube.

The tube construction of my invention includes separate sets of grid and late electrodes` in which are interposed lndividual cathodes with a relatively high resistance The resistance of the cathode is so selected that the usual 110 volt 60 cycle supply can be connected directly across the cathode. l The electron emitting portions of the cathode cooperating with the separated sets of grid and plate electrodes are externally connected in a control system in such manner thatv the plate electrodes in cooperation with each of the cathodes provide'means fordouble I wave rectification of the power supply for impresslng across the output circult of/ the tube direct current for the operation of any leo desired form of responsive device in the outl and plate electrodes are arranged. I have illustrated independent vplate electrodes 2 ly small e ectron emitting ortions 10 and 12, and central ortion 9. E ectron emitting portions 10 an 12 may have electron emltting coatings 16 and 17 thereover which become heated to an electron emitting temperature upon connection of the source of alternating current supply acrossl the leads 18 and 19 which connect with portions 14 and of the cathode structure.

In Fig. 1, I have illustrated diagrammatically the external connections for the electron tube system. The signaling energy to be ampliiied is passed through' prima winding 20 of transformer 21, which win ing is coupled with secondary winding 22.

1n the case of a detector, a rid leak and lao id condenser are connected etween winding 22 and grid electrodes 4' and 5 in lead 23. In an amplication circuit, the grid leak and ,grid condenser are omitted. Directly across the alternating current supply .circuit and leads 18 and 19 Iprovide a otentiometer 24 having a mid-tap 25 in which the opposite end ot winding 22 is connected and to which the end of the output circuit containing lead 26 is connected. A. responsivedevice 2? is interposed in the output circuit between the common connection 6 bridged between plates 2 and 3 and mid-tap on potentiometer 24.

Where the tubes are employed in cascade amplification the rimary winding 28 of transformer 29 is interposed in the Voutput, circuit of tube l and secondary winding 30 thereof connected at ene end with-mid-tap 25 ot potentiometer 24 and at the other end with grids 4 and 5a of the second tube 1a. The main terminals ot the filament 8a of tube la are connected to the power supply lines 31 and 32--through leads 18 and 19 but in a reverse manner to that in which filament 8 is connected through leads 18 and v19 with the power supply system. The output circuit of tube winding 33 of transformer 34 coupled with secondary winding 35 to any desired control circuit.

The resistance of each of the cathodes is arranged so that the usual 110 volt'lighting circuit power supply may be impressed directly thereacross. The length and compositionf of the cathode is such that while the two lntermediate portions 10 and 12 become 1 includes primary positive to an extent of fifty er cent of A the applied voltage across the fi ament. At this time plate electrode 2 is positive with respect to its filament l0, and provided the grid electrode 4 is of the proper polarity an electron stream will flow from filament 10 to plate 2 and current supply for the output circuit will pass through telephones 27 from plate electrode 2 across the electron stream to filament electrode 10. In a similar manner the sets of electrodes 12, 5 and 3 cooperate in rectifying the other half of the power supply cycle.

It Will be observed that the circuit arrangement which I have developed does not require the use of a transformer between the power supply system and the electron tube system. rlhe middle tap 25 on the potentiometer 24 may be eliminated by means of an additional terminal 36 brought out from a mid point of the cathode portion 9.' rihe tap. connection 36 connects to the middle electrical point of the cathode. lihis electrical center is the mid resist-ance point as between the mean potential point a of the electron emitting portion 10 and the point c of the other electron emitting portion. The tap 36 is taken off at`a point b in the portion 9 of the cathode in such manner that the resistanpe between ab and be is equal when the cathode is heated. The electron tube may be operated on any source ot A. C. supply, thatL is any voltage or frequency.

`The tube construction comprises the functions of A. C. rectication for the plate circuit, and detection and amplification of. signaling energy.

in the operation ot the electron tube system the tubes operate as double wave yrectifers for supplying uni-direction current to the output circuits thereof at the same time that the tubes are functioning as three electrode devices in the amplification or detection of signaling currents. it will be understood that various constructions of cathodes may be provided and that the form in which I have shown the cathode is merely illustrative of the principle of my invention, and that various modifications may be made in the construction of the device without departing from the spirit of my. invention. lt will also be understood 'that various forms of hum-preventing circuits may be provided in combinationv with the tube system grid and plate electrodes, a common cathode l lows l source, connections between opposite sides of said line circuit and said cathodes, and input and output circuits arranged between the grid and plate electrodes of each of said tubes with the output circuit of one of said tubes coupledywith the input circuit of the next adjacent tube, the next adjacent tube being coupled to the preceding tube in reverse order.

2. An amplification system comprising in combination a plurality of electron tubes, each of said electron tubes having sets of in each of said tubes for said sets of grid and plate electrodes, a source of alternating current, a line circuit connected with said source, connections between opposite sides of said line circuit and said cathodes, each of said cathodes having electron emitting portionsadjacent said sets of grid and plate electrodes, and means for balancing the drop across said catliodes substantially equal to the potential of said source, a potentiometer connected across saidline circuit, an input circuit for each of said tubes between the grid electrodes thereof, and a mid-point of said potentiometer, fan output circuit for each of said tubes between saidplate electrodes and a mid-point of 'said potentiometer, and means coupling the output circuit of one of said tubes to the input circuit of the nextadjacent tube, the cathode of the verse order to said line circuit. A 3. An amplifying system comprising in combination a source of alternating current,

next adjacent tube being connected in rea line system connected with said source, a

plurality of electron tubes each including sets of grid and plate electrodes, a cathode common to each of said sets of grid and j plate electrodes, said cathode having a resistance value for securing a potential drop thereacross substantially equal to the potential of said source, said electron tubes having input and output circuits interconnecting said grid and plate electrodes, with the 'next adjacent tube connecting with said lin'e 65 system in reverse order with respect to said preceding tube.

4. A n electronV tube system comprising in combination a source of alternating current,

an evacuated vessel, sets of grid and plate electrodes contained within said vessel, a common cathode, having separate electron emitting portions adjacent each of said sets of grid and plate electrodes, and a resistance between said electron emitting portions for obtaining a potential drop across the terminals of said cathode substantially equal to the potential o fsaid source, an input circuit including said grid electrodes, an output circuit including said plate electrodes,a 80

potentiometer connected across said source, and said input and output circuits terminating at a mid-point on said potentiometer, connections between said source and opposite termina-ls of said cathode, whereby said 35 plate electrodes cooperate with said cathode for double phase rectication `of alternating current obtainedfrom said source for 'supe' plying uni-directional current to said output circuit.

In testimony whereof I affix my signature.

CLINTON W. HOUGH. 

